Clevinger is a character in Joseph Heller's classic novel Catch-22. Like Yossarian, Clevinger is part of an air crew in a bomber squadron operating out of a small island in the Mediterranian.

Clevinger is a complete opposite of Yossarian, in his completely naïve view of the world. During his training he is put on trial for no apparent reason. In this trial, which is one of the most powerful reflections on human character throughout the book, Clevinger learns how someone you don't even know can badly want to kill you. He is put on trial by Lieutenant Scheisskopf, who is the prosecutor, defence lawyer, and one of 3 judges. There is no formal charge against him, other than the suspicion by Scheisskopf that he was smart, and therefore troublesome. Charges are added during the course of the trial for trivial things such as not saying "Sir" to an officer and is grilled as to the exact timing of when he didn't tell Yossarian about his thoughts on the trial. This trial is Heller's way of describing the most absurd bureaucracy.

Despite this experience, throughout his service in Pianosa, Clevinger still exhibits a complete lack of cyncism, and, some would argue, realism. He refuses to accept Yossarian's theory about everybody trying to kill him, until he himself vanishes with his plane into a cloud. His whereabouts are never known, although Yossarian believes there's a possibility that Clevinger went AWOL.